Question

的解决方案

我只能提出这样的解决方案：

import json

from mptt.utils import tree_item_iterator
from rest_framework import generics
from rest_framework.response import Response

from .models import Category

def tree_family_items_to_json(instances):
    data = ''
    channel = '"{}"'.format(instances[0].channel.slug)
    for category, structure in tree_item_iterator(instances):
        if structure['new_level']:
        data += '{'
        else:
            data += '],'
            data += '"channel": {}'.format(channel)
            data += '},{'
        data += '"slug": "{}",'.format(category.slug)
        data += '"name": "{}",'.format(category.name)
        data += '"subcategories": ['
        for level in structure['closed_levels']:
            data += '],'
            data += '"channel": {}'.format(channel)
            data += '}'

    return json.loads(data)

class CategoryFamily(generics.RetrieveAPIView):
    lookup_field = 'slug'
    queryset = Category.objects.all()

    def retrieve(self, request, *args, **kwargs):
        instances = self.get_object().get_family()
        json_data = tree_family_items_to_json(instances)
        return Response(json_data)

关键是我使用了tree_item_iterator来自mptt，现在我正在寻找更有趣的东西。

适合需要一段时间。但现在确定了多久。

有什么想法吗？

Answer 1

这是一种方法，以使树结构处于静止api：

# serializers.py
class CategoryTreeSerializer(ModelSerializer):
    children = SerializerMethodField(source='get_children')
    class Meta:
        fields = ('children',)  # add here rest of the fields from model 

    def get_children(self, obj):
        children = self.context['children'].get(obj.id, [])
        serializer = CategoryTreeSerializer(children, many=True, context=self.context)
        return serializer.data


 # views.py
 class CategoryViewSet(viewsets.ModelViewSet):

    queryset = Category.objects.all()
    serializer_class = CategoryTreeSerializer

    @detail_route()
    def tree(self, request, pk=None):
        """
        Detail route of an category that returns it's descendants in a tree structure.
        """
        category = self.get_object()
        descendants = category.get_descendants() # add here any select_related/prefetch_related fields to improve api performance

        children_dict = defaultdict(list)
        for descendant in descendants:
            children_dict[descendant.get_parent().pk].append(descendant)

        context = self.get_serializer_context()
        context['children'] = children_dict
        serializer = CategoryTreeSerializer(category, context=context)

        return Response(serializer.data)

在我的情况下，你得到一个新的端点（取决于你的url），它将是这样的：category/<category_pk>/tree，你可以在其中获得指定类别的树结构。

我们的想法是获取所有后代并为每个父级填充children_dict，这将传递给序列化程序的上下文，以避免多次查询。

Answer 2

您可以使用djangorestframework-recursive来获得更多便利。

views.py

from rest_framework import viewsets, generics
from yourapp.serializers import CategorySerializer
from yourapp.models import Category

class CategoryViewSet(viewsets.ModelViewSet):
    queryset = Category.objects.root_nodes()
    serializer_class = CategorySerializer

serializers.py

from rest_framework import serializers
from yourapp.models import Category
from rest_framework_recursive.fields import RecursiveField

class CategorySerializer(serializers.ModelSerializer):
    children = RecursiveField(many=True)

    class Meta:
        model = Category
        fields = ['id', 'name', 'children']

如何序列化Django MPTT系列并使其保持层次结构？

2 个答案: